Cable sockets and cable socket wedges are used to secure cables to machine elements, particularly to secure large diameter wire ropes to such machine elements as drag lines, hoist lines, and other lines employed with drag line buckets used in open face mining operations.
Drag line buckets are used for moving large quantities of earth and rock. The bucket is dragged across the mine surface by large cables, scooping up earth and rock. The cables that carry and drag the bucket, especially those that drag along the surface of the earth, must be replaced periodically.
Large drag line buckets have volumetric capacities in excess of one hundred cubic yards. The wire ropes employed to drag and hoist such large drag line buckets are typically about four inches in diameter or more. Such large diameter cables are difficult to work with.
Cables are usually secured to the bucket, or to chains connected to the bucket, by cable sockets and cable socket wedges. The cable is first fed through the socket, leaving a large loop. Then a wedge is placed in the socket and the cable is pulled down over the wedge, tightening the wedge into the socket. The edges of the wedge and the inside surfaces of the socket press on the cable, retaining it in the socket.
Replacing worn cables can be a major undertaking. Because of the tremendous forces involved in dragging and hoisting the bucket, the cable socket wedges can become very tightly wedged in the cable socket. Because of the large scale of the equipment, downtime, for cable replacement or any other reason, is very expensive. Thus quick cable replacement is needed.
One approach to quick cable replacement is to replace the entire socket, and to remove the used socket from the mine site to a shop having a large hydraulic ram with which to remove the wedge from the socket. This approach can produce considerable inconvenience, especially in the case of a relatively remote mine site.
Another approach, is to remove the wedge from the socket by blasting it out with explosives. This approach involves obvious hazards.
In response to the need presented by the above-described conditions, various easy-out wedge designs have been proposed and even utilized in the past. But none of the attempted designs has been both reliable in service and easily removable at the end of service. Wedges that hold up during service, particularly with wire rope diameters approaching four inches or larger, are not easily removable for cable replacement. Wedges that are more easily removable can fail during service, particularly with larger cable diameters and larger dragline bucket sizes.